Conventionally, a seat driving device has been proposed in, for example, Patent Document 1. The seat driving device includes a rotary motor, operation members, and clutch mechanisms. The operation members are separately arranged to correspond to position adjustment mechanisms provided on the seat. The clutch mechanisms are separately arranged to correspond to the position adjustment mechanisms. In response to operation of any one of the operation members, the clutch mechanisms selectively connect the corresponding position adjustment mechanism to the rotary motor. In response to operation of any one of the operation members, the rotary motor is energized with the polarity corresponding to the operation direction of the operation member.
Rotation of the rotary shaft of the rotary motor is transmitted to each clutch mechanism via a gear train of a skew arrangement composed of a worm provided on the rotary shaft and a worm wheel provided on the input shaft of each clutch mechanism.